Lapping machine



June 19, 1934. J, G, H, Bum:v

LAPPING MACHINE Filed March 7, 1953 ,'55 shown in Fig; 1'.

Patented June 19, 1934 EATENT roIr-"icE 1,963,884.v `1`.PPING MAHINE John George Holtzapffel Budd, st. Pancras,

England Application March 7, 1933Y Serial No.,659,967 In Great Britain March 8, 1932 9 Claims.

This invention relates to that kind of machine designed for lapping studs, rollers and other cylindrical articles which it is desired to .bring quickly to accurate and uniformsize and where- 5 in the articles to be lapped are held by a `workholder or plate movable between a positively rotated lap and a stationary lap and controlled by a bearing member. A lapping machine of this kind has been proposed in which the workholder 10 or plate is mounted upon and freely rotatable about an eccentric bearing member which is positively driven to rotate at a definite speed, preferably different to that of the positively rotated lap. Y

The present invention relates to improvements in lapping machines of the type referred to, and it has for its object to enable the workholder or plate (hereinafter called the workholder), to be operated in a better manner than heretofore and also to improve in other respects the'construction and operation of lapping machines.

For this purpose a lapping machine of the kind wherein a workholder is arranged between `a positively rotated lap and a stationary lap is characterized according to the present invention, by the fact that the bearing member for the workholder is caused to rotate about the axis of the laps with a speed different to that of the rotating lap and with a variable amount of eccentricity aboutV the axis of the laps, by means of epicyclic gearing one end gear member of which is connected to the bearingrmember and is capable of radial adjustment with respect kto the axis of the rotating lap and the other end gear member of` which is arranged co-axial with and connected to therotary platform for the rotary lap so as to rotate therewith.

The invention further consists in providing the improved lapping machine withmeans for the removal from the laps and workholder of excess of abrasive or lubricant, or both, used therewith, which might otherwise collect in the centre of the lap, or lap' carrying portion of the machine, or which may be thrown o at the periphery of the same.

A lapping machine embodying the invention can be variously constructed. l Y

In the accompanying illustrative drawing, Fig. l shows in vertical section, one construction of lapping machine according to the present invention. Figs. 2 and 3 are views to a larger scale than Fig. l, showing respectively in Aelevation partly in section, and in plan,- one construction of the bearingI member and epicyclic gearing Fig.4 shows in plan, part of fchine.

a workholder suitableY for use in lapping the peripheral surfaces of cylindrical articles.

Referring to Fig. 1, the lower lap, namely 1, of the two lap members 1 and 2, is mounted upon a rcircular platform provided with a raised lip or hollow boss 4 karound the central portion thereof and with a circular depression 5 around the outer side of ther lip or boss, communicating with a series of radial channels 6 yformed in the face of the platform 3 and arranged to slope 65 downwards and outwards to the periphery of the same. The lower lap 1 is formed as a at ring having i internally projecting lugs or arms 1 which engage against corresponding lugs or abutments 3a, shown as pins, provided on the plat- 70 form 3, so that the lap 1 is constrained to rotate with the platform, at the vsame time leaving suflicient clearance space between the inner side of the lap and lthe outer sideof the boss 4 to allow of excess lubricant or/and abrasiven to flow over the inner edge of the laplsurface into the circular depression whence it isfree to flow down the channels 6 to the periphery of the platform' Clips or holding down bolts may be provided for thepurpose of keeping thelap in close contact with the surface of the platformif desired, but in mostcases the weight of the lap is found sufficient for this purpose. t, The circular platform 3 carrying'the lower lap 1 is supported, through the intermediary of a ball bearing rI upon theupper end vof a tubular vertical bearing '7a carried by the,frame 8 of the ma- The platform is xed'as by a nut 3b, to the upperreduced end of a hollow vertical spindle 9 mounted to rotate inthe fixed bearing 'la and adapted t'o be rotated by suitable driving means, as for instance bevel gearing 10, 10a, from a'horizontal driving shaft 11 adapted to be driven,

,it may .be through AVariable speed gearing 11a, 'from a' suitable prim'e lmover direct, or by pulleys and belting Yfrom line shafting.

. Within the hollow boss 4-is located a bearing member with'which is associated Vepicyclic gearing bymeans of which it andthe workholder controlled thereby can be caused to revolve about the axis of theplatform 3 and lap 1 in an improved manner. :The said mechanism comprises,

`as shown in Figs. 2 and 3, a gear wheel 13 having any suitable number of teeth, for example 63,

and provided with a hollow downwardly extend- 105 'ing .portion 14'adapted toy be placed within the upper end portion of thehollow spindle 9. The

`said wheel 13 is provided with pins 15 adapted t'oengage` in slots' formed'within the upper por- 13 will be rotated by the said spindle and it and the platform 3 will rotate together. Above the gear wheel 13 is mounted a support comprising a plate 16, or crank arm, free toV rotate about the axis of the gear wheel 13 and platform 3. For this purpose the plate 16 is provided with a downward extension 17 which passes through the gear wheel 13 and into its extension 14 and is prevented from rising but not from rotating therein by means of a plate 18 and stud 19. Arranged at a suitable position on the upper surface of the plate or crank arm 16 is a lug 16a having a central hole in which runs a spindle 20 carrying on its lower end a gear wheel 21 having any suitable number of teeth, for example 12, in

mesh with the gear wheel 13. Upon the plate 16 is mounted a similar plate 22 which can be turned about the lug 16"1 on the plate 16 and means are provided for clamping the two plates together in any particular angular position relative to one another that may be desired. Such means may comprise, for example, a screw stud 23 arranged to extend through a curved slot 24 in the plate 22 and into a screw threaded hole in the plate 16. The spindley 20 in the lug 16a projects through both plates 16 and 22 and carries on its upper end a gear wheel 25 having any suitable number of teeth, for example 63, meshing with a gear wheel 26 having any suitable number of teeth, for example 12, to which is keyed the bearing member 27 carrying the workholder 28 (Fig. 4). The gear wheel 26 is free to rotate with the bearing member 27 upon a stud 29 fixed in a suitable position to the plate 22. Thus it will be seen that by adjusting the relative angular positions of the two plates 16 and 22, if the numbers of teeth in the two pairs of gear wheels 13-21 and 25-26, and their pitches are suitably selected, it will be possible to adjust the axis of the gear wheel 26 and of the stud 29 radially with respect to the axis of the lap 1 so asto bring the axis of the stud 29 in line with the axis of the lap 1 and platform 3, or to give it a position of varying eccentricity with regard to that axis. l Y

` The bearing member 27 is provided with three eccentrically arranged parallel driving pins 30 which correspond with three circularly disposed holes 31 in the central portion of the workholder 28, (Fig. 4)Y and as the work pieces, which are located in slots 28a arranged at a slight angle to the adjacent radii in the workholder 28, rotate between the rotating and non-rotating laps 1 and 2, they cause the workholder to rotate at a speed approximately half that of the rotating lap, thus causing the workholder to turn the bearing member 27, through the three pins 30, at a different speed to the gear wheel 13 fixed to and rotating with the platform 3 and the lap 1. As a result, the two combined plates 16 and 22 are caused to rotate relatively to the lap 1 about the axis of the platform and lap by virtue of the epicyclic train formed by the four gear wheels 13, 21, 25 and 26, and consequently the axis of the bearing member 27, assuming it to be xed in an eccentric position relative to the axis of the platform 3, will be caused to travel around the said axis at a different angular speed to that of the,platform, the exact ratio of the speeds being determined by the numbers of teeth in the gear wheels.

The upper lap 2 is of a similar form to the lower one 1, but provision is made for bolting or otherwise securing it to a vertically disposed shaft which is prevented from rotating but is free to be moved in a direction to or away from the lower lap. For this purpose, as shown in Fig.. 1`,the

ipeasfi upper lap 2 is carried by a backing 47 to which it is iixed by a number of clips 48, one end of each of which engages a recess 2iL in the lap while its other end embraces the upper surface of the backing 47, studs 49 being provided for holding the clips in position. The backing 47 is carried bya vertical spindle 50 slidably mounted in a bush 50a carried by the split end 51a of a bracket 51, the other end 51b of which is also split and mounted to turn about a vertical pivot pin 52 carried byra standard 53. Clamping means 54 are provided for causing the split end 51a of the bracket to hold the spindle 50 and bush 50a in position vertically and clamping means 55 are provided for holding the bracket 5l to the pivot pin 52.

Means are provided to permit a small amount of play between the upper lap 2 and its support to enable the lap to adjust itself horizontally to any slight irregularities in alignment of the surfaces of the two laps. For this purpose, in the example shown in Fig. 1, the backing 47 has a trunnion block 56 journalled at its ends 56a in the said backing and having laterally projecting pins 56b to which the lower fork-shaped end of the spindle 50 is connected. Means are also provided for raising the upper lap by means of its spindle 50, as for instance by means of a hand wheel 57 working as a nut on the screw-threaded upper end portion of the spindle, and acting on the bush 50a through a ball bearing 58. Also, the upper lap 2 and spindle 50 can be moved to one side of the machine for the purpose 0f reloading the carrier or workholder, or for examination of the lower lap, by loosening the clamping means 55 'and turning the bracket 5l to one side of the machine. Spring means may, if necessary, be provided adapted to allow of variation of the pressure of the upper lap upon the article being lapped. For this purpose, a spiral spring 59, may, as shown in Fig. l, be placed around the vertical spindle 50 between the ball race 58 and the hand wheel 57, thus allowing the upper lap to rest freely with its full weight upon the articles or to be partially supported by the spring, the amount of such partial support being regulated by the setting of the handwheel 57 and the consequent compression of the spring.

vAn annular tray 60 may, as shown in Fig. 1, be xed to the bed plate of the machine in such a position as to catch lubricant and/or abrasive, thrown off by the above mentioned channels 6 in the platform 3 and by the outer periphery of the lower lap l, the tray having a suitable valve controlled outlet pipe 61 to enable an accumula-V tion of lubricant and/ or abrasive to be drawn off therefrom as required.

The laps may be arranged to be reversible so that both the upper and lower surfaces of either or both laps may be charged with the abrasive material, thus allowing for the use of two different qualities or kinds of abrasive, without recharging the said laps, merely by reversing them after use with one abrasive and thus bringing into juxtaposition a second pair of surfaces charged with the other abrasive.

What I claim is:-f y

1. A lapping machine having a stationary lap, a positively rotated lap, a workholder mounted between said laps and adapted to hold cylindrical articles to be lapped and means adapted by rotation of the workholder caused by rotation of articles between the laps to cause the workholder to rotate with a speed different to that of they rotary lap and with a gyratory motion about the axis of the laps.

2. A lapping machine according to claim l provided with means for varying the extent of the gyratory motion of the Workholder.

3. A lapping machine comprising a positively rotated lap, a stationary lap, a workholder between said laps, a bearing member connected to and movable with said workholder, and epicyclic gearing whereby said workholder and bearing member can rotate about the axis of said laps with a speed different to that of the rotary lap and with an adjustable amount of eccentricity about the axis of the laps, one end gear member of said epicyclic gear being connected to said bearing member and radially adjusted therewith in a horizontal plane and the other end gear member of said gearing being arranged co-axial with said rotary lap and rotatable therewith.

4. A lapping machine comprising a positively rotated lap, a stationary lap, a workholder between said laps, a rotary support arranged to rotate co-axial with said rotary lap, a bearing member connected to and movable horizontally with said workholder and radially adjustable in a horizontal plane upon said support and epicyclic gearing one end gear member of which is connected to said bearing member and radially adjustable in relation to the axes of said rotary support, and the other end gear member of which is coaxial with said rotary lap and rotatable therewith.

5. A lapping machine comprising a positively rotated lap, a stationary lap, a workholder between said laps, a bearing member connected to and movable with said workholder, a support mounted to turn about the axis of said rotary lap, a spindle mounted in said support, a toothed wheel xed to said spindle, a toothed wheel connected to said bearing member, radially adjust able above said support about a vertical axis and in gear with the toothed wheel fixed to said spindle, a second toothed wheel xed to said spindle, and a toothed wheel arranged to rotate with said rotary lap and in gear with the second toothed wheel on said spindle.

6. A lapping machine according to claim 4 wherein said rotary support comprises upper and lower members, the Lipper of which carries the associated toothed wheel with bearing member and is radially adjustable in a horizontal plane on the lower member which is mounted to turn about the axis of said rotary lap and means for clamping the upper and lower members of said support together in any desired relative radial position.

7. A lapping machine comprising a stationary support having a vertical bearing, a driving spindle in said bearing, a rotary platform mounted on said bearing and connected to said spindle, a lower lap in driving connection with said rotary platform, an upper stationary lap, a workholder between said laps, a bearing member connected to and movable with said workholder, and epicyclic gearing comprising a toothed wheel having a lower tubular bearing mounted in the upper end of said driving spindle and in driving connection with said spindle, a rotary support having a lower cylindrical extension arranged to rotate in said tubular bearing, a vertical spindle mounted in said rotary support, and eccentrically to its lower extension, a plate adjustable upon said rotary support about the spindle carried thereby, a vertical spindle mounted in said plate andconnected to said bearing member and so arranged that it can be brought by adjustment of said plate into a position above the axis of said lower tubular extension or into a position eccentric thereto, a toothed wheel fixed to the last mentioned spindle, means for clamping said rotary support and plate together in any desired adjusted position of the latter, and toothed wheels fixed to the lower and upper ends of the spindle carried by the rotary support and in gear respectively with the lower toothed wheel connected to the rotary platform and the toothed wheel connected to said bearing member.

8. A lapping machine according to claim 7, wherein the upper end of the driving spindle is provided with slots and the lower adjacent toothed wheel of the epicyclic gearing is provided with pins adapted, by vertical movement of said epicyclic gearing and bearing member as a unit, to be placed in and out of engagement with said 115 slots and thereby in and out of driving connection with said spindle.

9. A lapping machine, comprising a stationary support, a rotary platform mounted thereon, driving means for said platform, a stationary tray 120 surrounding said rotary platform and a lap mounted on and in driving connection with said platform, said platform being provided with a centrally arranged upper tubular extension, with an annular groove around said extension and 12 with drain channels extending from said groove to the outer periphery of said platform for the purpose set forth.

JOHN GEORGE HOLTZAPFFEL BUDD. 

